Porting ACE, TAO, and CIAO to a New OS Platform
ACE, TAO, and CIAO have been
ported to many
OS platforms. Porting ACE, TAO, and CIAO to new platforms is
fairly easy. The following document describes the step-by-step
process to use when porting the various components
and layers in ACE to a new OS platform. Once ACE is ported, it is
straightforward to port TAO and CIAO, as well.
Before starting a port that you plan to contribute back to the
ACE+TAO+CIAO open-source community, we recommend that you do the
following:
- Read and follow the programming style
guidelines we use when writing ACE, TAO, and CIAO code,
which will make it much easier to integrate and maintain your port
in the source tree.
- Contact Douglas
C. Schmidt and let him know that you're planning to contribute
a port, which will make it make easier to work out the logistics
of when/how the port will be integrated.
Create a config.h
Header File for the Target OS Platform
A config-*.h
header file exists in $ACE_ROOT/ace for each platform to which ACE has
been ported. This file contains the portability macros for each
particular configuration of ACE. A complete description of the
existent macros can be found in the $ACE_ROOT/ace/README file.
Currently, you must edit this file by hand to port it to new OS
platforms. It's a good idea to use
the config-*.h
files for platforms with similar
characteristics as examples.
Port the ACE_OS
Namespace
The ACE_OS
namespace encapsulates most of variation
between the different OS implementations, e.g., UNIX, Win32,
and various real-time operating systems. It is the core of the ACE OS
abstraction layer. Most work required to port ACE to a new OS
platform resides in this namespace. There are many examples
of how ACE has been ported to other operating systems in the
ACE_OS
class in the
$ACE_ROOT/ace/OS_NS_*.{h,inl,cpp}
files.
Optional features in pthreads are covered by ACE_HAS_*
and/or ACE_LACKS_*
macros, which are described in the $ACE_ROOT/ace/README file. Particular
platform features, such as DCE pthreads calls that end in
_np
, should be bracketed by platform defines rather than
by inventing more ACE_HAS_*
or ACE_LACKS_*
definitions.
An important part of porting ACE to a new platform is to map the
threading API correctly. Currently, ACE has support for the following
thread APIs:
- UNIX International (UI) Threads
(
ACE_HAS_STHREADS
) - Solaris.
- POSIX Pthreads (
ACE_HAS_PTHREADS
) -Final standard (also
called draft 10) [MIT, Linux, and Solaris].
- Win32 Threads (
ACE_HAS_WTHREADS
) - Windows
NT, Windows '95/98, and Windows CE
- VxWorks Tasks (
ACE_VXWORKS
) - VxWorks
If your OS platform does not support any of these threading packages,
you must port the ACE_OS::thr_*
functions.
Port the C++ Wrapper Facade Components
After porting the ACE_OS
namespace, the next step is to
port all of the ACE C++ wrapper facade components, such as sockets,
threads, synchronization mechanisms. A full list of the categories
and classes can be found in the $ACE_ROOT/ACE-categories file. It is
easiest to concentrate on porting one category at the time. The ACE
release contain a regression test suite
in the $ACE_ROOT/tests/ directory. These
tests can be used to validate the correctness of the various ACE C++
wrapper facades as they are ported.
Port the Higher-level Framework Components of ACE
Having ported (and tested) all the components of the ACE OS adaptation
layer and C++ wrapper facades, you can proceed to port the higher
level components of ACE, such as the Reactor, Service Configurator,
Connector, Acceptor, and Streams frameworks. At this point, it should
be relatively easy to port the rest of ACE because most of the
platform-dependent code is localized in the lower layers of ACE.
Port TAO and CIAO
After porting and successfully testing all the ACE framework
components, it should be straightforward to port and install TAO and install CIAO because the bulk
of their platform-dependent code is localized in ACE. Typically, the
only problems that arise when porting TAO and CIAO is bugs and
limitations with C++ compilers.
C++ Features Required to Port ACE, TAO, and CIAO
ACE, TAO, and CIAO have been ported to most C++ compilers. The
following is a list of which C++ features a compiler must support in
order to compile ACE and TAO:
- Templates -- The C++ compiler must support templates.
However, it need not support template member functions and of
the advanced concepts outlined in Modern C++ Design.
- Multiple inheritance and dynamic binding -- The C++
compiler must support multiple inheritance and dynamic
binding.
- Namespaces -- ACE+TAO+CIAO utilizes C++ namespaces, so the
C++ compiler must support them.
- ANSI casts and RTTI -- ACE+TAO+CIAO uses the ANSI C++
casts, so the C++ compiler must support them, which implies
support for RTTI.
The following is a list of which C++ features that ACE, TAO, CIAO can
take advantage of if a compiler supports them:
- Exceptions -- The ACE library itself is ``exception
neutral,'' i.e., it does not catch or throw C++
exceptions. However, you can use exceptions in code
that uses ACE including throwing exceptions inside call back
methods, as long as you provide the code to handle it.
TAO requires the use of C++ exceptions,
ACE_HAS_EXCEPTIONS
must be defined.
- STL -- Unfortunately many of the platforms that ACE
supports don't have an STL library. Moreover, different versions
of STL behave differently. ACE therefore does not depends on
STL and does not use it internally. If your target
platform(s) support STL you should be able to
use it with ACE, TAO, and CIAO without problems, though your C++
compiler may have problems with it (this is beyond the scope
of ACE, however).
If you are considering STL, you might consider
STLport,
which is a port of the SGI STL to numerous platforms that ACE,
TAO, and CIAO also support.
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